Optically active materials of derivatives of 3a,8b-cis-dihydro-3H-cyclopenta [b] benzofuran, which is a tricyclic compound, are conventionally synthesized by optical resolution of [7-bromo-3a,8b-cis-dihydro-3H-cyclopenta [b] benzofuran-5-yl] formic acid with an optically active amine, as disclosed in Japanese Unexamined Patent Publication No. 59-161371, or by enzyme reaction thereof, as disclosed in J. Chem. Soc., Chem. Commun., 811, 1995. However, there has been not known yet a simplest direct method of obtaining optically active materials by asymmetric synthesis.